Overhead tow conveyor



A. R. BElTzEl. ETAL 3,265,012

OVERHEAD TOW CONVEYOR Aug, 9, 1966 3 Sheets-Sheet 1 Filed March 20, 1964 u @d mw mmm /iillilllm s im Un M ff r i @wp Y 5R77 NHA l mwwfw/ MANI? Aug. 9, 1966 A. R. BEI-HEL ET AL 3,265,012

OVERHEAD TOW CONVEYOR Filed March 20. 1964 3 Sheets-Sheet 2 INVENTORJ Aug. 9, 1966 A. R BEn-ZEL ETAL 3,265,012

OVERHEAD Tow coNvEYoR Filed March 2o, 1964 3 sheets-sheet s INVENTORS ARVf/Vf A. f/rzfz.

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United States Patent 3,265,012 OVERHEAD TW CONVEYGR Arvene R. Beitzel, Atlanta, Ga., Augustus E. Green, Charlotte, N.C., and Howard L. Meyer, Wilton, Conn.,

assignors to Jervis B. Webb Company, a corporation of Michigan Filed Mar.20, 1964, Ser. No. 353,496 10 Claims. (Cl. 104-170) This invention relates to improvements in the construction of an overhead tow conveyor for floor trucks, and particularly to an improved pusher for coupling a tow mast of a door truck to an overhead tow line.

A conventional overhead tow conveyor includes an overhead track on which the trolleys, endless chain, and pushers of the tow line are mounted, and wheeled trucks which travel on a floor or other `supporting surface beneath the tow line, each truck being equipped with an opstanding tow mast engageable with and disengageable from a tow line pusher.

The principal objects of the invention are to provide an improved tow mast and pusher construction which securely retains the tow mast in coupled engagement with the pusher; which results in improved control over tow truck movement up and down inclines; which permits automatic uncoupling of the tow mast from a pusher for switching a iloor truck to either side of a main tow line; and which permits the tow mast of a floor truck to be disengaged or engaged with a pusher anywhere along a level portion of the tow conveyor.

In general, the construction of the invention is characterized -by the tow mast consisting of an upstanding member of xed length having its lower end secured to the ioor truck and an enlarged cap at its upper end, each pusher having portions which extend -downwardly and inwardly into underlying relation with the tow mast cap, and where the tow conveyor includes a section along which the elevation is changed, such a section is arranged with the pushers in increased vertical spacing from a floor truck so that the loor truck is in part suspended from a pusher by engagement between the tow mast cap and the downwardly and inwardly extending pusher portions while traversing such section.

In other respects a pusher constructed in accordance with the invention lis characterized by having a pair of side mem-bers extending parallel to and a pusher member extending -transversely to the direction of travel, the side members and pusher member 'being mounted on suitable ybase structure in depending relation therewith to overlap the upper end of a tow mast, the side members being spaced apart a distance such as to guide the upper end of a tow mast into engagement with the pusher member and terminating forwardly of the pusher member so as to leave a side opening adjacent the pusher member through which the upper end of a tow mast can be moved in a disengaging direction generally transverse to the direction of pusher travel, a retainer movably carried by the pusher and normally blocking the side opening, and means for moving the retainer to a non-blocking position to permit a tow mast to be disengaged from the pusher by relative movement in a direction transverse to the direction of pusher travel.

.The retainer can be moved to such a non-blocking position 'by a cam and follower arrangement operable in response to pusher travel to permit the tow truck to be disengaged by a switch or a diverter, and also by a manually operable release member. Preferably, the pusher also includes a holdback member which prevents a tow mast sfrom moving forwardly relative to the pusher.

Other features and advantages of the construction will appear from the following description of the presently preferred representative embodiment thereof shown in the accompanying drawings in which:

FIGURE 1 is a side elevation of an overhead tow line showing a change in horizontal elevation;

yFIGURE 2 is a schematic plan view of a junction between a main and branch line;

FIGURE 3 is an enlarged side elevation of a pusher and upper end of a tow mast taken as indicated by the line 3-3 of FIG. 2;

FIGURE 4 is a sectional elevation on the longitudinal center line of the pusher illustrated in FIG. y3;

FIGURE 5 is a sectional plan view taken as indicated by the line 5 5 of FIG. 3;

FIGURE 6 is a sectional plan View taken as indicated by the line 6 6 of FIG. 3; and

FIGURE 7 is a sectional elevation similar to FIG. 4 Ibut showng the tow mast retainer manually moved to releasing position.

Referring to FIGS. 1 and 3, a wheeled floor truck 10 is provided with a tow mast 12 which is rigidly secured to the front end of the truck by suitable structure 13. The tow mast 12 is of xed length and is provided at its upper end 15 with an enlarged cap 16. The floor truck is propelled along a supporting surface 18 by engagement between the upper end of the tow mast 12 and a pusher of an overhead tow line; the tow line including an overhead track 22, trolleys 24 riding thereon and engaged by an endless chain 26 driven by a suitable driving device (not shown).

Each pusher 20 consists of a base plate 30 iirmly secured to an adjacent pair of trolleys 24 as shown in FIG. 3. A pair of side members 31 and 32 and a transverse member 33 are secured to and depend from the base plate 30, each side member being provided with an inwardly extending portion or ange 34 (FIG. 6), and the transverse member 33 being provided with a portion 36 which serves as a pusher member. The portions 34 and 36 extend inwardly and underlie the tow mast cap 16; the side member portions 34 `being spaced apart a distance such as to guide the upper end 15 of a tow mast 12 into engagement with the pusher member 36. As shown in FIGS. 3 6, each of the side members 31 and 32 including their inwardly extending flanges 34 is cut away forwardly of the pusher member 36 to provide a side opening through which the upper end 15 and enlarged cap 16 of a tow mast can be moved in a direction transverse to the direction of pusher travel.

Toward the forward end of the pusher 20 a pivot pin 38 is mounted between the pusher side members 31-32 at a level above the upper end of the tow mast 12. A pair of holdback members 40 and 41 are each freely pivoted on the pin 38 adjacent the pusher side members 31 and 32 respectively (FIG. 5) and are interconnected to move in unison by a cross member 43. A retainer 46 is also pivoted on the pin 38 and consists of a tongue 47 secured at one end to a sleeve 48 `through which the pin 38 extends, and having an enlarged T-shaped opposite end 50 with a pair of depending side anges 51 and 52 each adapted to normally obstruct movement of the tow mast through the opening of the side plate 31 and 32 respectively. Followers 54 and 55 are secured to the depending retainer flanges 51 and 52. Both the retainer 46 and holdback members 40-41 are normally urged by gravity about the pivot pin 38 in a clockwise direction as the parts are viewed in FIGS. 3 and 4 to operative positions defined by the side anges 34.

Referring to FIG. 1 and to FIG. 7, the tow mast 12 is tubular and a release rod `58 is slidably mounted within it, extending from a conveniently accessible level to the upper end 15 of the tow mast. An operating handle 59 is secured to the release r-od 58 near the lower end thereof and extends through a bayonet type of slot 60 in the tow mast wall so that the release rod can be manually moved between and held in a lower normal position shown in FIG. 1 and a raised position shown in FIG. 7.

Operation of the tow conveyor is as follows: A floor truck is manually positioned so that the upper end 15 i of its tow mast lies in the path of travel of an oncoming pusher of the tow line, and is thus engaged between the depending side plates 31 and 32 of the pusher and guided |by the inwardly extending flanges 34 thereof into contact with the pusher member 36. As the pusher 20 moves forwardly relative to the tow mast, the enlarged cap 16 of the tow mast engages and moves both the holdback members 40 and 41 and the retainer 46 upwardly about the pivot 38. During this movement the upper ends 62 (FIG. 4) of the holdback members 40 and 41 may project through clearance slots 64 provided in the pusher base plate 3d. When the enlarged tow mast cap 16 has moved rearwardly of the holdback members, they will automatically drop down and rest upon the upper surface of the side flanges 34 and serve to limit movement of the tow mast forwardly of the pusher. The end portion 50 of the retainer rests upon the upper surface of the tow mast cap 16, and in this position the retainer side flanges 51 and 52.1imit lateral movement of the tow mast relative to the pusher and obsrtuct the openings in the side plates of the pusher. The pusher member 36 and side anges 34 form inwardly directed portions of the pusher which underlie the tow mast cap 16 when the upper end 15 of the tow mast engages the pusher member 36, as best shown in FIGS. 3 and 6. It can thus be seen that the tow mast and its enlarged cap 16 are interlocked in engagement with the pusher assembly.

When the tow line extends through a change in vertical elevation, as shown by the inclined portion 66 of the supporting surface in FIG. 1, the relative spacing between the supporting surface and tow line track 22 is increased along the track section 68 so that the pusher is moved upwardly relative to the tow mast and lthe inwardly extending pusher portions 34 and 36 engage the overlying tow mast cap 16 so that the front end of the floor truck is picked up and suspended from the pusher. This results in improved control over tow truck movement on inclines and declines and eliminates the necessity for providing guiding devices to prevent the floor truck from over turning.

In the event it is desired to include a branch line in the tow conveyor, as shown in FIG. 2, guide rails 70 and '72 are usually provided along the main and branch paths of travel as indicated for more accurately stabilizing the position of the tow mast for proper engagement between it and a switch or diverter 74. Automatic release of the tow mast from the pusher is accomplished by the provision of a cam track 76 having upwardly and downwardly inclined entrance and exit portions 77 and 78, positioned so as to tbe engaged by one of the followers 54 or 55 on the retainer 46 of a pusher assembly. When this engagement takes place the retainer 46 is moved upwardly and held in an elevated position while the pusher moves by the switch 74; and, if the switch is thrown to branch line position the switch will engage the tow mast and direct it transversely of the pusher 20 through one of the side openings thereof. If the switch is not thrown to branch line position the pusher and tow mast move through the switch on the main line, and even though the retainer is raised to a non-blocking position, the switch 74 and guide rails 70 hold the tow mast in centered relation with the pusher until the retainer follower passes out of engagement with the cam track 76.-

Manual disengagement of a floor truck from a pusher can be accomplished anywhere along the tow line, but preferably not where a floor truck is suspended therefrom, by merely raising the release rod 58 to the position shown in FIG. 7, thus elevating the retainer to a nonblocking position and permitting the tow mast to be moved transversely of the pusher through either of the side openingsl thereof. During this movement the retainer end portion 50 slides on the upper end of the release rod 58 until one of the retainer side flanges 51 or 52 is over the top of the tow mast cap 16, and so the tow mast is easily disengaged from the pusher and retainer by relative transverse movement.

While preferred embodiments have been described above in detail, it will be understood that numerous modifications might be resorted to without departing from the scope of the invention as dei-ined in the following claims.

We claim:

1. An overhead tow conveyor including an overhead power chain provided with pushers for engaging a tow mast of a floor truck, characterized by the tow mast consisting of an upstanding member having its lower end fixed to the floor truck, an enlarged cap at the upper end of the tow mast, each pusher having portions which extend downwardly and inwardly into underlying relation with the tow mast cap, and a section along which the elevation of the conveyor is changed, said section being arranged with the pushers in increased vertical spacing from a oor so that a iloor truck is in part suspended from a pusher by engagement between the tow mast cap and the downwardly and inwardly extending pusher portions while traversing said section.

2. An overhead tow conveyor including an overhead power chain provided with pushers for engaging a tow mast of a floor truck characterized by each pusher having a pair of side members extending parallel and a pusher member extending transversely of the direction of travel, base structure on which said side members and pusher member are mounted in depending relation to overlap the upper end of a tow mast, said side members being spaced apart a distance such as to guide the upper end of a tow mast into engagement with said pusher member, an opening in a side member adjacent said pusher member through which opening the upper end of a tow mast can be moved in a direction generally transverse -to the direction of pusher travel, a retainer movably carried by the pusher and normally blocking said transverse tow mast movement, and means for moving said retainer to a non- -blocking position to permit a tow mast to be disengaged from the pusher by relative movement in a direction transverse to the direction of pusher travel.

3. An overhead tow conveyor as claimed in claim 2 further characterized by the means for moving the retainer to a nonblocking position including a cam track, means mounting `said cam track laterally adjacent the path of pusher travel, and a follower member secured to said retainer and projecting laterally from the pusher for engagement with said cam track, said cam track being arranged to cause movement of the retainer to nonblocking position when engaged by said follower.

4. A tow conveyor as claimed in claim 2 further characterized by said means for moving the retainer to a nonblocking position including a release member movably carried by the tow mast and extendable from the upper end thereof, said retainer including a portion overlying said release member, and means for manually extending said release member to move the retainer to nonblocking position.

5. A tow conveyor as claimed in claim 2 further characterized by said retainer being pivotally supported between said pusher side members forwardly of said opening, said retainer extending from said pivotal mounting to overlap said opening and having a depending side portion at least partially overlapping the upper end of a tow mast engaged with said pusher member.

6. A tow conveyor as claimed in claim 2 further characterized by a tow mast holdback member movably carried between the pusher side members.

7. A tow conveyor as claimed `in claim 2 further characterized by said tow mast having an enlarged cap secured to the upper end thereof, said pusher having portions which extend into underlying relation with said cap, said underlying portions being adapted to engage the underside of said cap and lift the tow mast and tow truck wheen the distance between the tow line and floor is increased.

8. A lpusher for an overhead tow line for engaging an upstanding tow mast, said pusher comprising a base portion, means for securing the base portion to the tow line, a depending pusher member secured to said base portion and extending transversely to the direction of tow line travel, a pair of depending side members secured to said base portion, said side members being transversely spaced apart `a distance suicient to permit the upper end of a tow mast to pass therebetween and being spaced forwardly from said pusher member a distance such as to leave an opening through which the upper end of a tow mast can be moved in a direction transverse to the direction of tow line travel, and a retainer supported by the pusher structure for normally urged movement to a position in which said opening is obstructed by at least a portion of said retainer.

9. A tow conveyor pusher as claimed in claim 8 wherein said retainer comprises a plate-like member pivotally supported between said pusher side members, said retainer including a portion extending transversely between said side members and engageable by the upper end of a tow mast and a pair of depending anges each adapted to overlap at least a portion of a tow mast and normally obstruct movement thereof through one of sad openings.

10. A pusher according to claim 9 further characterized by a tow mast holdback member pivotally supported with said retainer on the same axis, said retainer and holdback member being independently pivotally movable.

References Cited by the Examiner UNITED STATES PATENTS 2,949,862 8/1960 Klamp- 104-88 3,043,236 7/1962 Sgricca 104-172 3,059,587 10/1962 Dickson et al. 104-88 ARTHUR L. LA POlNT, Primary Examiner.

F. W. MONAGHAN, R. A. BERTSCH,

Assistant Examiners. 

1. AN OVERHEAD TOW CONVEYOR INCLUDING AN OVERHEAD POWER CHAIN PROVIDED WITH PUSHERS FOR ENGAGING A TOW MAST OF A FLOOR TRUCK, CHARACTERIZED BY THE TOW MAST CONSISTING OF AN UPSTANDING MEMBER HAVING ITS LOWER END FIXED TO THE FLOOR TRUCK, AN ENLARGED CAP AT THE UPPER END OF THE TOW MAST, EACH PUSHER HAVING PORTIONS WHICH EXTEND DOWNWARDLY AND INWARDLY INTO UNDERLYING RELATION WITH THE TOW MAST CAP, AND A SECTION ALONG WHICH THE ELEVATION OF THE CONVEYOR IS CHANGED, SAID SECTION BEING ARRANGED WITH THE PUSHERS IN INCREASED VERTICAL SPACING 